In the production of flanged axle shafts for automoblies, the axle shaft often includes a button portion which is a cylindrical element having a generally flat outwardly facing surface and spaced from the splined section of the axle shafts by an undercut portion. This button is used for supporting the shaft within the differential and must be hardened and tempered for wear resistance and strength. In the past, several systems have been used for performing this process. Generally the buttons are heated separately by an induction heating coil and then quench hardened. Thereafter, tempering is accomplished by a furnace or a subsequent induction heating operation wherein the hardened button is tempered at a lower temperature than the hardening temperature. Since a single workpiece was processed by prior systems, a substantial amount of processing time was required and individual handling was necessitated. The present invention relates to an improved method and apparatus for accomplishing the hardening and tempering of the button portion of an axle shaft, which method and apparatus use induction heating and process several workpieces simultaneously and automatically.